Direct Gas Make-Up Air
25
Burner Differential
Pressure Sensor
(Optional) High Gas
Pressure Switch
(Optional) Low Gas
Pressure Switch
Manual Pilot
Shut-Off Valve
Pilot Gas Pressure
Test Port
Pilot Solenoid
Pilot Regulator
Burner Gas
Pressure Test Port
Burner Manual
Shut-Off Valve
Modulating
Valve
Safety Shut-Off Valves
Regulator
Airflow
Typical Pilot System with Separate Modulating Valve and Regulator
Typical Pilot System with Combined Modulating Regulator
Burner Differential
Pressure Sensor
Pilot Solenoid
Pilot Regulator
Burner Gas
Pressure Test Port
Burner Manual
Shut-Off Valve
Safety Shut-Off Valves
Pilot Gas Pressure
Test Port
Modulating/Regulator
Valve
Airflow
(Optional) High Gas
Pressure Switch
(Optional) Low Gas
Pressure Switch
Manual Pilot
Shut-Off Valve
Pre-Start: Direct Gas-Fired Heating
Gas Train Identification